After the fall of Rome he left the city at the head of 4000 volunteers, with the idea of joining the defenders of Venice, and started on that wonderful retreat through central Italy pursued by the armies of France, Austria, Spain and Naples.
Many of its native Christian defenders emigrated to Dalmatia and Italy; others took refuge in the mountains with the Roman Catholic Ghegs.
On the 10th of September he stormed Drogheda, and by his order the whole of its 2800 defenders were put to the sword without quarter.
The cause of the republic was brilliantly advocated by Fra Paolo Sarpi, counsellor of state; the defenders of the papal theory were Cardinals Baronius and Bellarmine.
Garibaldi quitted the city, followed by 4000 of his men, and attempted to join the defenders of Venice.